Audio feedback in PA systems can cause problems ranging from irritation to equipment damage. The feedback phenomenon may occur, for example, when loudspeaker audio is re-captured by a microphone and re-amplified continuously, forming a feedback loop exceeding the system's stability margin. The method used in most small PA systems to eliminate audio feedback is to simply lower the loudspeaker volume until room audio no longer squeals and howls. More sophisticated PA systems may be acoustically treated with wall-mounted panels and Digital Signal Processor (DSP) parametric equalizers (PEQs). Another method of attempting to eliminate audio feedback is to add an automatic feedback elimination device to the PA system itself.